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1 | /* $OpenBSD: cipher-3des1.c,v 1.6 2006/08/03 03:34:42 deraadt Exp $ */ | |
2 | /* | |
3 | * Copyright (c) 2003 Markus Friedl. All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * | |
14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
15 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
16 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
17 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
18 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
19 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
20 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
21 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
22 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
23 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
24 | */ | |
25 | ||
26 | #include "includes.h" | |
27 | ||
28 | #include <sys/types.h> | |
29 | ||
30 | #include <openssl/evp.h> | |
31 | ||
32 | #include <stdarg.h> | |
33 | #include <string.h> | |
34 | ||
35 | #include "xmalloc.h" | |
36 | #include "log.h" | |
37 | ||
38 | #include "openbsd-compat/openssl-compat.h" | |
39 | ||
40 | /* | |
41 | * This is used by SSH1: | |
42 | * | |
43 | * What kind of triple DES are these 2 routines? | |
44 | * | |
45 | * Why is there a redundant initialization vector? | |
46 | * | |
47 | * If only iv3 was used, then, this would till effect have been | |
48 | * outer-cbc. However, there is also a private iv1 == iv2 which | |
49 | * perhaps makes differential analysis easier. On the other hand, the | |
50 | * private iv1 probably makes the CRC-32 attack ineffective. This is a | |
51 | * result of that there is no longer any known iv1 to use when | |
52 | * choosing the X block. | |
53 | */ | |
54 | struct ssh1_3des_ctx | |
55 | { | |
56 | EVP_CIPHER_CTX k1, k2, k3; | |
57 | }; | |
58 | ||
59 | const EVP_CIPHER * evp_ssh1_3des(void); | |
60 | void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int); | |
61 | ||
62 | static int | |
63 | ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv, | |
64 | int enc) | |
65 | { | |
66 | struct ssh1_3des_ctx *c; | |
67 | u_char *k1, *k2, *k3; | |
68 | ||
69 | if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) { | |
70 | c = xmalloc(sizeof(*c)); | |
71 | EVP_CIPHER_CTX_set_app_data(ctx, c); | |
72 | } | |
73 | if (key == NULL) | |
74 | return (1); | |
75 | if (enc == -1) | |
76 | enc = ctx->encrypt; | |
77 | k1 = k2 = k3 = (u_char *) key; | |
78 | k2 += 8; | |
79 | if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) { | |
80 | if (enc) | |
81 | k3 += 16; | |
82 | else | |
83 | k1 += 16; | |
84 | } | |
85 | EVP_CIPHER_CTX_init(&c->k1); | |
86 | EVP_CIPHER_CTX_init(&c->k2); | |
87 | EVP_CIPHER_CTX_init(&c->k3); | |
88 | #ifdef SSH_OLD_EVP | |
89 | EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc); | |
90 | EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc); | |
91 | EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc); | |
92 | #else | |
93 | if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 || | |
94 | EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 || | |
95 | EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) { | |
96 | memset(c, 0, sizeof(*c)); | |
97 | xfree(c); | |
98 | EVP_CIPHER_CTX_set_app_data(ctx, NULL); | |
99 | return (0); | |
100 | } | |
101 | #endif | |
102 | return (1); | |
103 | } | |
104 | ||
105 | static int | |
106 | ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, u_int len) | |
107 | { | |
108 | struct ssh1_3des_ctx *c; | |
109 | ||
110 | if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) { | |
111 | error("ssh1_3des_cbc: no context"); | |
112 | return (0); | |
113 | } | |
114 | #ifdef SSH_OLD_EVP | |
115 | EVP_Cipher(&c->k1, dest, (u_char *)src, len); | |
116 | EVP_Cipher(&c->k2, dest, dest, len); | |
117 | EVP_Cipher(&c->k3, dest, dest, len); | |
118 | #else | |
119 | if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 || | |
120 | EVP_Cipher(&c->k2, dest, dest, len) == 0 || | |
121 | EVP_Cipher(&c->k3, dest, dest, len) == 0) | |
122 | return (0); | |
123 | #endif | |
124 | return (1); | |
125 | } | |
126 | ||
127 | static int | |
128 | ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx) | |
129 | { | |
130 | struct ssh1_3des_ctx *c; | |
131 | ||
132 | if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) { | |
133 | EVP_CIPHER_CTX_cleanup(&c->k1); | |
134 | EVP_CIPHER_CTX_cleanup(&c->k2); | |
135 | EVP_CIPHER_CTX_cleanup(&c->k3); | |
136 | memset(c, 0, sizeof(*c)); | |
137 | xfree(c); | |
138 | EVP_CIPHER_CTX_set_app_data(ctx, NULL); | |
139 | } | |
140 | return (1); | |
141 | } | |
142 | ||
143 | void | |
144 | ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len) | |
145 | { | |
146 | struct ssh1_3des_ctx *c; | |
147 | ||
148 | if (len != 24) | |
149 | fatal("%s: bad 3des iv length: %d", __func__, len); | |
150 | if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL) | |
151 | fatal("%s: no 3des context", __func__); | |
152 | if (doset) { | |
153 | debug3("%s: Installed 3DES IV", __func__); | |
154 | memcpy(c->k1.iv, iv, 8); | |
155 | memcpy(c->k2.iv, iv + 8, 8); | |
156 | memcpy(c->k3.iv, iv + 16, 8); | |
157 | } else { | |
158 | debug3("%s: Copying 3DES IV", __func__); | |
159 | memcpy(iv, c->k1.iv, 8); | |
160 | memcpy(iv + 8, c->k2.iv, 8); | |
161 | memcpy(iv + 16, c->k3.iv, 8); | |
162 | } | |
163 | } | |
164 | ||
165 | const EVP_CIPHER * | |
166 | evp_ssh1_3des(void) | |
167 | { | |
168 | static EVP_CIPHER ssh1_3des; | |
169 | ||
170 | memset(&ssh1_3des, 0, sizeof(EVP_CIPHER)); | |
171 | ssh1_3des.nid = NID_undef; | |
172 | ssh1_3des.block_size = 8; | |
173 | ssh1_3des.iv_len = 0; | |
174 | ssh1_3des.key_len = 16; | |
175 | ssh1_3des.init = ssh1_3des_init; | |
176 | ssh1_3des.cleanup = ssh1_3des_cleanup; | |
177 | ssh1_3des.do_cipher = ssh1_3des_cbc; | |
178 | #ifndef SSH_OLD_EVP | |
179 | ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH; | |
180 | #endif | |
181 | return (&ssh1_3des); | |
182 | } |